/* 全局样式 */
* {
  box-sizing: border-box;
}

body {
  background-color: steelblue; /* 页面背景颜色 */
  color: #fff; /* 文字颜色 */
  font-family: 'Muli', sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh; /* 页面高度 */
  overflow: hidden;
  margin: 0;
}

.container {
  background-color: rgba(0, 0, 0, 0.4); /* 半透明背景 */
  padding: 20px 40px;
  border-radius: 8px;
}

.container h1 {
  text-align: center;
  margin-bottom: 30px;
}

.container a {
  text-decoration: none;
  color: lightblue;
  transition: color 0.3s;
}

.container a:hover {
  color: white;
}

.btn {
  cursor: pointer;
  display: inline-block;
  width: 100%;
  background: lightblue;
  padding: 15px;
  font-family: inherit;
  font-size: 16px;
  border: 0;
  border-radius: 5px;
  transition: background-color 0.3s, transform 0.2s ease;
}

.btn:focus {
  outline: none;
}

.btn:hover {
  background-color: #1e90ff;
  transform: scale(1.02); /* 轻微放大 */
}

.btn:active {
  transform: scale(0.98);
}

.text {
  margin-top: 30px;
}

.form-control {
  position: relative;
  margin: 20px 0 40px;
  width: 300px;
}

.form-control input {
  background-color: transparent;
  border: none;
  border-bottom: 2px solid #fff;
  display: block;
  width: 100%;
  padding: 15px 0;
  font-size: 18px;
  color: #00a2fa;
  transition: border-color 0.3s ease;
}

.form-control input:focus,
.form-control input:valid {
  outline: none;
  border-bottom-color: lightblue; /* 聚焦时变为浅蓝色 */
}

.form-control label {
  position: absolute;
  top: 15px;
  left: 0;
  pointer-events: none;
  transition: transform 0.3s, color 0.3s;
}

.form-control label span {
  display: inline-block;
  font-size: 18px;
  min-width: 5px;
  opacity: 1;
  transform: translateY(10px);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.form-control input:focus + label span,
.form-control input:valid + label span {
  opacity: 1;
  transform: translateY(-30px);
  color: lightblue;
}

/* 复选框样式 */
.checkbox {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 20px;
}

.checkbox input[type="checkbox"] {
  width: 20px;
  height: 20px;
  cursor: pointer;
  accent-color: lightblue; /* 现代浏览器支持的样式，用于更好地控制复选框颜色 */
  border-radius: 4px;
  transition: transform 0.2s ease;
}

.checkbox input[type="checkbox"]:hover {
  transform: scale(1.2); /* 放大效果 */
}

.checkbox label {
  font-size: 16px;
  cursor: pointer;
  transition: color 0.3s ease;
}

.checkbox input[type="checkbox"]:checked + label {
  color: lightblue; /* 选中后变为浅蓝色 */
}

.checkbox label:hover {
  color: white; /* 悬停时文字颜色变白 */
}
